Anything that can be saved or exported as an image (jpeg, png, gif): inspiration, wordle, create a graph, comic life, snapshots of anything on desktop, paint images, moticam pictures can be saved as images. (Remember to rename your pictures so that it is a unique name.)
Sildeshow sites: Bubbleshare , Slide,
Insert documents using google docs
Add Podcasts and small movies as you would a picture.
Create great word images using flickr pictures with Spell with Flickr

Embed interesting items in the wiki by using the embed icon (looks like a TV and choose "more html"): Voki, Scribd or docstoc, Blabberize, Voicethread, or Widgets such as

Can use the Embed widget function (looks like a TV icon in the edit bar) to add the following examples. Many other sites that offer similar applications can also embed (use the "more html" embed box.)

Other sites that list tools: